package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

import org.apache.lucene.index.PayloadProcessorProvider.DirPayloadProcessor;

final class SegmentMergeInfo {
    Term term;
    int base;
    int ord; // the position of the segment in a MultiReader
    TermEnum termEnum;
    IndexReader reader;
    int delCount;
    private TermPositions postings; // use getPositions()
    private int[] docMap; // use getDocMap()
    DirPayloadProcessor dirPayloadProcessor;

    SegmentMergeInfo(int b, TermEnum te, IndexReader r) throws IOException {
        base = b;
        reader = r;
        termEnum = te;
        term = te.term();
    }

    // maps around deleted docs
    int[] getDocMap() {
        if (docMap == null) {
            delCount = 0;
            // build array which maps document numbers around deletions 
            if (reader.hasDeletions()) {
                int maxDoc = reader.maxDoc();
                docMap = new int[maxDoc];
                int j = 0;
                for (int i = 0; i < maxDoc; i++) {
                    if (reader.isDeleted(i)) {
                        delCount++;
                        docMap[i] = -1;
                    } else
                        docMap[i] = j++;
                }
            }
        }
        return docMap;
    }

    TermPositions getPositions() throws IOException {
        if (postings == null) {
            postings = reader.termPositions();
        }
        return postings;
    }

    final boolean next() throws IOException {
        if (termEnum.next()) {
            term = termEnum.term();
            return true;
        } else {
            term = null;
            return false;
        }
    }

    final void close() throws IOException {
        try {
            termEnum.close();
        } finally {
            if (postings != null) {
                postings.close();
            }
        }
    }
}
